Overview
ASIL determination is the automatic result of combining your Severity, Exposure, and Controllability assessments. The HARA Risksheet applies the ISO 26262-3 Table D.5 risk matrix formula to compute the ASIL rating (QM, A, B, C, or D) for each hazard.Steps
1. Complete S-E-C Assessment
Before ASIL values can appear, ensure each hazard has all three risk parameters assigned:- Severity (S0-S3) — Potential harm level
- Exposure (E0-E4) — Frequency of operational situation
- Controllability (C0-C3) — Driver’s ability to prevent harm
2. Switch to HARA Classification View
In the HARA Risksheet, select the ** HARA Classification** workflow view from the view dropdown. This focuses the display on the risk assessment columns:| Column | Purpose |
|---|---|
| Severity (S) | S0-S3 rating |
| Exposure (E) | E0-E4 rating |
| Controllability (C) | C0-C3 rating |
| ASIL | Auto-calculated QM/A/B/C/D |
3. Review Auto-Calculated ASIL Values
The Risksheet formula automatically computes ASIL using the ISO 26262-3 risk matrix:
4. Check ASIL Color-Coding
The Risksheet applies color-coded cell decorators to ASIL values for visual risk prioritization:| ASIL | Color | Safety Integrity Requirement |
|---|---|---|
| QM | Gray | Quality Management only |
| A | Green | Low functional safety rigor |
| B | Orange | Moderate safety requirements |
| C | Light Red | High safety rigor |
| D | Purple | Maximum safety integrity |
5. Validate ASIL Distribution
Click the ** Full View** to see all hazards with their ASIL ratings. Verify the distribution makes sense:6. Document ASIL Rationale
For each ASIL C or D hazard, add justification in the Hazard Description or Operational Situation column explaining:- Why the combination of S-E-C leads to this severity level
- Real-world scenarios that drive the Exposure rating
- Driver limitations that affect Controllability
Verification
You should now see:- ✅ All hazards display an ASIL value (QM, A, B, C, or D) with color-coding
- ✅ No “Pending” ASIL cells (all S-E-C assessments complete)
- ✅ ASIL distribution follows expected project risk profile
- ✅ High-ASIL hazards (C/D) have documented rationale
What Happens Next
ASIL values propagate downstream to Safety Goals:- Each hazard’s ASIL automatically flows to its linked Safety Goal via the
inheritASILformula - Safety Goals carry the ASIL rating to Functional Safety Requirements (ISO 26262-4)
- Design Requirements inherit ASIL from parent Safety Requirements
- Verification testing scope is determined by ASIL level (e.g., ASIL D requires independent assessment)
See Also
- Assess Severity, Exposure, and Controllability — Set the S-E-C input values
- Derive Safety Goals — Create Safety Goals from ASIL-rated hazards
- ASIL Classification System — Understand the five ASIL levels
- HARA Risksheet Configuration — Formula and matrix details
- ASIL Classification (QM, A-D) — Enumeration reference
- ISO 26262 HARA Report — View ASIL distribution statistics